Dielectronic capture processes in highly charged uranium ions

Pindzola, M. S.; Badnell, N. R.

doi:10.1103/physreva.42.6526

Cited by 40 publications

(32 citation statements)

References 16 publications

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“…The code can make use both of nonrelativistic and semi-relativistic wavefunctions (Pindzola & Badnell 1990). The low-n problem is no different from the one of computing atomic structure.…”

Section: Dielectronic Recombination Rate Coefficient Modellingmentioning

confidence: 99%

Dielectronic recombination data for dynamic finite-density plasmas

Badnell

O’Mullane

Summers

et al. 2003

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Abstract.A programme is outlined for the assembly of a comprehensive dielectronic recombination database within the generalized collisional-radiative (GCR) framework. It is valid for modelling ions of elements in dynamic finite-density plasmas such as occur in transient astrophysical plasmas such as solar flares and in the divertors and high transport regions of magnetic fusion devices. The resolution and precision of the data are tuned to spectral analysis and so are sufficient for prediction of the dielectronic recombination contributions to individual spectral line emissivities. The fundamental data are structured according to the format prescriptions of the Atomic Data and Analysis Structure (ADAS) and the production of relevant GCR derived data for application is described and implemented following ADAS. The requirements on the dielectronic recombination database are reviewed and the new data are placed in context and evaluated with respect to older and more approximate treatments. Illustrative results validate the new high-resolution zero-density dielectronic recombination data in comparison with measurements made in heavy-ion storage rings utilizing an electron cooler. We also exemplify the role of the dielectronic data on GCR coefficient behaviour for some representative light and medium weight elements.

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“…The code can make use both of nonrelativistic and semi-relativistic wavefunctions (Pindzola & Badnell 1990). The low-n problem is no different from the one of computing atomic structure.…”

Section: Dielectronic Recombination Rate Coefficient Modellingmentioning

confidence: 99%

Dielectronic recombination data for dynamic finite-density plasmas

Badnell

O’Mullane

Summers

et al. 2003

A&A

Self Cite

225

282

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“…While the semirelativistic approach of AUTOSTRUCTURE cannot hope to give energy splittings to high precision in such highly relativistic systems (and so makes use of the best available N-electron energies instead [6]), its description of radiative and autoionization rates has been shown to be accurate, at least for l =0-5 [1]. There being no obvious reason why the semirelativistic approach should fail for high l, we have reexamined the problem.…”

mentioning

confidence: 94%

“…Multiconfiguration Dirac-Fock (MCDF) calculations were carried out for the 2p 3/2 6l resonances, and for l =0-5 of the 2p 1/2 nl resonances (for n ജ 20). The contribution from higher l for the 2p 1/2 nl resonances was determined using the multiconfiguration BreitPauli (MCBP) semirelativistic approach incorporated within the AUTOSTRUCTURE code [6], which includes the massvelocity and Darwin terms within the solution of the radial equations. Subsequently, measurements were made at GSI [2] for DR via the 2p 1/2 20l resonances and these were found to be in good agreement with MCDF calculations [2], which were made for all l. Good agreement was found also with the MCDF results of Mitnik et al [4], but the semirelativistic results reported by them were found to be a factor of 3 smaller than the measurements and MCDF results of Brandau et al [2].…”

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confidence: 99%

Dielectronic recombination ofPb79+via high angular momenta

et al. 2004

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We have used the AUTOSTRUCTURE code to carry out semirelativistic calculations for the dielectronic recombination of Pb 79+ via the 2s 1/2 −2p 1/2 core excitation. We obtain excellent agreement between these semirelativistic results and measurements made at Gesellschaft für Schwerionenforschung, in particular, for the high angular momentum peak of the 2p 1/2 20l j resonances. The factor of 3 underestimate in the result for this peak that was originally obtained by Mitnik et al., which has led some to conclude that only a fully relativistic approach can describe dielectronic recombination via high angular momenta in very heavy highly charged ions, are found to be in error. DOI: 10.1103/PhysRevA.70.054701 PACS number(s): 34.80.KwDielectronic recombination (DR) of very heavy highly charged Li-like ions has been a testbed for experimental and theoretical studies of relativistic effects in DR [1][2][3][4][5]. The heavy-ion Experimental Storage Ring (ESR) at Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, has been used to test quantum electrodynamics (QED) in strong fields by measuring the series of DR resonances occurring via a 2s 1/2 −2p 1/2 core excitation so as to determine the coreenergy splitting to high precision [2,3]. The DR resonances themselves are particularly interesting because the relatively small 2s 1/2 −2p 1/2 energy splitting means that DR via high angular momentum states (to l ϳ 20) makes a significant contribution to the n-resolved total.Prior to measurements at GSI, Mitnik et al.[4] carried out calculations for the DR of Pb 79+ over 0 -300 eV. This covered all DR resonances that arise via the 2s 1/2 −2p 1/2 core excitation and the first ͑n =6͒ resonances associated with the 2s 1/2 −2p 3/2 core excitation. Multiconfiguration Dirac-Fock (MCDF) calculations were carried out for the 2p 3/2 6l resonances, and for l =0-5 of the 2p 1/2 nl resonances (for n ജ 20). The contribution from higher l for the 2p 1/2 nl resonances was determined using the multiconfiguration BreitPauli (MCBP) semirelativistic approach incorporated within the AUTOSTRUCTURE code [6], which includes the massvelocity and Darwin terms within the solution of the radial equations. Subsequently, measurements were made at GSI [2] for DR via the 2p 1/2 20l resonances and these were found to be in good agreement with MCDF calculations [2], which were made for all l. Good agreement was found also with the MCDF results of Mitnik et al. [4], but the semirelativistic results reported by them were found to be a factor of 3 smaller than the measurements and MCDF results of Brandau et al. [2]. This led [2] to conclude that "Contributions from very high angular momenta must be included and considered in a fully relativistic framework in order to understand the dynamics involved in the DR process."While the semirelativistic approach of AUTOSTRUCTURE cannot hope to give energy splittings to high precision in such highly relativistic systems (and so makes use of the best available N-electron energies instead [6]), its description of r...

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“…The  code (Badnell 1986;Badnell & Pindzola 1989;Badnell 1997) is used to calculate multiconfiguration intermediate coupling energy levels, radiative rates and autoionization rates. The code can make use both of non-relativistic and semi-relativistic wavefunctions (Pindzola & Badnell 1990). The calculations have been produced in intermediate coupling (IC) approximation.…”

Section: Theorymentioning

confidence: 99%

“…Prior to the final DR calculations, the ionic thresholds were shifted to the known spectroscopic values (http://physics.nist.gov/cgi-bin/ AtData/main_asd) by a small amount -typically in the range of 1-2 eV for high Z. The calculations for Ti 15+ , and beyond, were performed in the semirelativistic approximation for the radial wave functions, developed by Cowan & Griffin (1976) and implemented in  as is explained in Pindzola & Badnell (1990). Non-relativistic radial functions were used otherwise.…”

Section: Theorymentioning

confidence: 99%